Vacuum stability and supersymmetry at high scales with two Higgs doublets

TL;DR

This paper explores the stability of the electroweak vacuum in two-Higgs doublet models with a supersymmetric UV completion, revealing conditions for vacuum stability, the role of superpartners, and potential signatures of high-scale supersymmetry.

Contribution

It demonstrates that two-Higgs doublet models can be matched to supersymmetric UV completions at high scales, unlike the Standard Model, and identifies key parameters influencing vacuum stability and experimental signatures.

Findings

Vacuum stability favors low tan(beta) < 2

Pseudoscalar masses are at least about a TeV

Light higgsinos are a promising signature of high-scale supersymmetry

Abstract

We investigate the stability of the electroweak vacuum for two-Higgs doublet models with a supersymmetric UV completion. The supersymmetry breaking scale is taken to be of the order of the grand unification scale. We first study the case where all superpartners decouple at this scale. We show that contrary to the Standard Model with one Higgs doublet, matching to the supersymmetric UV completion is possible if the low-scale model contains two Higgs doublets. In this case vacuum stability and experimental constraints point towards low values of tan(beta) < 2 and pseudoscalar masses of at least about a TeV. If the higgsino superpartners of the Higgs fields are also kept light, the conclusions are similar and essentially independent of the higgsino mass. Finally, if all gauginos are also given electroweak-scale masses (split supersymmetry with two Higgs doublets), the model cannot be matched to supersymmetry at very high scales when requiring a 125 GeV Higgs. Light neutral and charged higgsinos therefore emerge as a promising signature of a supersymmetric UV completion of the Standard Model at the grand unification scale.